Microwaves travel linearly, can be focused into a unidirectional beam, and can effectively heat the human body to the depth of skeletal tissues even when the patient is clothed. Therefore, applications using microwaves to treat the living body are being increasingly studied.
Many such applications, however, are still at the stage of research. Practical applications are limited to therapy of stiff shoulders and lumbagos by using microwaves for accelerating circulation and improving metabolism by utilizing the heating effect thereof.
Subsequent research on microwaves established a sure and accurate control of local heating by controlling the intensity and direction of super microwaves of 12.24 cm to thereby cause them to reach the desired tissues within the living body.